The excess-flow lockout (and the slow-open fix)
Every modern propane cylinder valve has an excess-flow safety: if gas rushes out faster than expected — like when you snap the valve open onto empty lines — a little check ball seats and chokes flow to a trickle. Result: burners that barely light, a furnace that tries and gives up, and an owner convinced the regulator died.
Reset it: turn off the tank valve and every appliance, wait a minute or two for pressures to equalize, then open the tank valve slowly — a half turn at first. Wait, then open fully. Make that slow open a habit every time and the lockout never bites again.
How the two-stage regulator works (and fails)
The regulator drops tank pressure (well over 100 PSI on a hot day) to the 11 inches of water column your appliances burn at — that's about 0.4 PSI, a remarkably gentle pressure. Two stages do it in steps, which is why RV regulators have that double-dome look.
They fail with age: diaphragms stiffen, vents clog, and output drifts weak or erratic. Symptoms are weak yellow flames everywhere, appliances that fade when a second one starts, or a regulator that hums or freezes over in normal weather (frost during heavy draw in humid weather can be normal; ice in mild use isn't). Regulators are sealed and non-serviceable, and the standard guidance is replacement roughly every 10 years, or sooner at the first symptom.
Check the whole supply chain
Between tank and regulator sit the pigtail hoses — and their internal check valves can fail and choke flow on one side of an auto-changeover setup. If flames strengthen when you switch the changeover to the other tank, a pigtail is your culprit; they're cheap parts.
On auto-changeover regulators, make sure the selector points at a tank that's actually open and full, and remember the indicator shows red when the selected tank is empty and it's feeding from the reserve. Half of "propane problems" at 6 a.m. are an empty selected tank.
Leak-test like a tech: soapy water, never a flame
Any time you disturb a propane fitting — new regulator, new pigtail, tank swap — leak-test it: a 50/50 mix of dish soap and water brushed on every joint with the gas on and appliances off. Growing bubbles mean a leak; snug the fitting and retest. Never, ever hunt a gas leak with a lighter, and don't rely on smell alone outdoors where wind carries the odorant away.
If you smell gas inside the rig: no switches, no flames — shut the tank valve, open windows and doors, get out, and let it air before you diagnose. A propane detector at floor level (propane sinks) is mandatory equipment, and they expire — check the date on yours.
Stuck on this one? Put Major in your pocket.
Tell RV Journey Genie your make, model, and symptom and get a step-by-step fix — by text, voice, or photo — before you ever call the shop.
Frequently asked questions
Why are all my RV propane appliances suddenly weak at once?
A system-wide weakness points upstream: either the tank valve's excess-flow safety locked out because the valve was opened too fast, or the regulator is failing. Reset the lockout by closing the tank valve, waiting two minutes, then opening it very slowly. If weak flames persist, replace the regulator.
How often should an RV propane regulator be replaced?
About every 10 years, or immediately at symptoms like weak yellow flames on all appliances, output that fades under load, or humming. Regulators are sealed, non-repairable safety devices — replacement is inexpensive and new pigtails at the same time are cheap insurance.
How do I check for a propane leak on my RV?
Brush a 50/50 dish soap and water mix on every fitting you've disturbed with the tank valve on and appliances off — growing bubbles reveal a leak. Never test with a flame. Inside the rig, trust your floor-level propane detector and replace it by its expiration date; propane is heavier than air and pools low.